Clinical Significance of Persistent Hematuria Degrees in Primary IgA Nephropathy: A Propensity Score-Matched Analysis of a 10-Year Follow-Up Cohort

Introduction: The clinical significance of persistent hematuria degrees has not been expounded in primary IgA nephropathy (IgAN) and requires further research. Methods: From January 2003 to May 2022, a total of 684 IgAN patients with persistent hematuria were enrolled to conduct a retrospective single-center study. Patients whose hematuria degree at baseline was higher than the second tertiles of the whole were included in the high-degree hematuria cohort (Hh), and the low-degree hematuria cohort (Lh) was constructed with 1:1 matched cases from the rest according to age, gender, and estimated glomerular filtration rate (eGFR) at baseline and follow-up time. Survival was determined using the Kaplan-Meier method (K-M) and generalized linear mixed-effects model (GLMM). Risk factors for survival were determined according to the Cox proportional hazards model. Results: Both the Hh and Lh consisted of 228 cases. While the demographic data and the renal function at baseline were matched, both the K-M (p = 0.02) and GLMM (p = 0.04) proved that the prognosis of the Hh was significantly worse than that of the Lh within 10 years of follow-up. The higher persistent hematuria degree was an independent risk factor (3.93; 95% confidence interval, 1.33–11.6) associated with reaching the endpoint (eGFR decreased from the baseline ≥30% continuously or reached end-stage renal disease [ESRD]). The Hh had a significantly higher proportion of crescent (p = 0.003). The prognosis of the Hh was significantly worse than that of the Lh when accompanied by the crescent and presented an indistinct difference if the crescent was absent. Conclusions: The clinicopathologic manifestation of IgAN patients with persistent high-degree hematuria was severer, and the prognosis was worse than those with persistent low-degree hematuria.